u-boot support logo image.

u-boot 起來(排除 u-boot console wait time)  到 kernel logo show 出來會有段蠻常的時間 , 如果沒有任何 logo , 使用者可能會認為...當機 !!

好吧 , 加上 frame buffer driver 到 u-boot 上吧 !! 不過要先確認 backlit dirver 可以  working . backlit 比較簡單 , 所以就不說明了 !!

開始 lcd driver 移植到 u-boot 吧 !!


第一步驟 , 要先啟動 LCDC 相關的 clock / power domain .

#define CM_PER_LCDC_CLKCTRL         (CM_PER + 0x18) /* LCDC  */
#define CM_PER_LCDC_CLKSTCTRL       (CM_PER + 0x148)/* LCDC */

第二步驟 , 設定 LCDC 的 PLL Clock .
void disp_pll_clocks(void)
{

u32 clkmode, clksel, div_m2;

    clkmode = readl(CM_CLKMODE_DPLL_DISP);
    clksel = readl(CM_CLKSEL_DPLL_DISP);
    div_m2 = readl(CM_DIV_M2_DPLL_DISP);

    /* Set the PLL to bypass Mode */
    clkmode = (clkmode & 0xfffffff8) | 0x00000004;
    writel(clkmode, CM_CLKMODE_DPLL_DISP);
    while ((readl(CM_IDLEST_DPLL_DISP) & 0x00000100) != 0x00000100);

    clksel = clksel & (~0x7ffff);
    clksel = clksel | ((DISPPLL_M << 0x8) | DISPPLL_N);
    writel(clksel, CM_CLKSEL_DPLL_DISP);

    div_m2 = div_m2 & 0xFFFFFFE0;
    div_m2 = div_m2 | DISPPLL_M2;
    writel(div_m2, CM_DIV_M2_DPLL_DISP);

    clkmode = (clkmode & 0xfffffff8) | 0x7;
    writel(clkmode, CM_CLKMODE_DPLL_DISP);
    while ((readl(CM_IDLEST_DPLL_DISP) & 0x00000001) != 0x1);


}

第三步驟, 設定 LCD 相關 GPIO 的 function.

static struct module_pin_mux lcdc_pin_mux[] =
{

    {OFFSET(gpmc_csn3),   (MODE(7) | PULLUDEN)},    /* GPIO2_0 ,LCD_PWREN */

    {OFFSET(lcd_data0),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_0  */
    {OFFSET(lcd_data1),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_1  */
    {OFFSET(lcd_data2),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_2  */
    {OFFSET(lcd_data3),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_3  */
    {OFFSET(lcd_data4),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_4  */
    {OFFSET(lcd_data5),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_5  */
    {OFFSET(lcd_data6),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_6  */
    {OFFSET(lcd_data7),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_7  */
    {OFFSET(lcd_data8),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_8  */
    {OFFSET(lcd_data9),     MODE(0) | PULLUDEN},    /* Makesure lcd_data_9  */
    {OFFSET(lcd_data10),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_10 */
    {OFFSET(lcd_data11),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_11 */
    {OFFSET(lcd_data12),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_12 */
    {OFFSET(lcd_data13),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_13 */
    {OFFSET(lcd_data14),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_14 */
    {OFFSET(lcd_data15),    MODE(0) | PULLUDEN},    /* Makesure lcd_data_15 */

    {OFFSET(gpmc_ad15),     MODE(1) | PULLUDEN},    /* lcd_data_16 */
    {OFFSET(gpmc_ad14),     MODE(1) | PULLUDEN},    /* lcd_data_17 */
    {OFFSET(gpmc_ad13),     MODE(1) | PULLUDEN},    /* lcd_data_18 */
    {OFFSET(gpmc_ad12),     MODE(1) | PULLUDEN},    /* lcd_data_19 */
    {OFFSET(gpmc_ad11),     MODE(1) | PULLUDEN},    /* lcd_data_20 */
    {OFFSET(gpmc_ad10),     MODE(1) | PULLUDEN},    /* lcd_data_21 */
    {OFFSET(gpmc_ad9),      MODE(1) | PULLUDEN},    /* lcd_data_22 */
    {OFFSET(gpmc_ad8),      MODE(1) | PULLUDEN},    /* lcd_data_23 */

    {OFFSET(lcd_pclk),          MODE(0) | PULLUDEN},    /* lcd_pclk */
    {OFFSET(lcd_vsync),         MODE(0) | PULLUDEN},    /* lcd_vsync */
    {OFFSET(lcd_hsync),         MODE(0) | PULLUDEN},    /* lcd_hsync */
    {OFFSET(lcd_ac_bias_en),    MODE(0) | PULLUDEN},    /* lcd_ac_bias */


    {-1},
};

第四步驟, 在 video 下增加 driver file .
Make file 中多這項目. am335x_lcdc.c 需要由 kernel 那邊移植過來. 去掉 kernel 相關的部份.

COBJS-$(CONFIG_VIDEO_AM335X) += am335x_lcdc.o

第五步驟 , 在 am335_evm.h 中增加下列選項
u-boot 本身就有支援 lcd 的 driver library 了 , 所以要打開 CONFIG_LCD ,
另外SYS_CONSOLE_IS_IN_ENV 要打開 , 不然 console 會跑到 LCD 上 ,並非 UART.


/* LCD Support */
#define CONFIG_LCD
#ifdef CONFIG_LCD

 #define CONFIG_VIDEO_AM335X
 #define CONFIG_SYS_CONSOLE_IS_IN_ENV   // prevent console switch to LCD.

//---- select LCD type .
 #define CONFIG_LCD_TM050RBH01

//---- setting logo file name
 #define CONFIG_LOGO_FILE_NAME   "inst_logo.raw"

//---- enable backlit support.
 #define CONFIG_CMD_BACKLIT


#endif

最後一個步驟 ,在 lcd.h 中增加 相關的 struct 欄位, 這個欄位最後和 kernel 的相同,
這樣移植過程比較順利..


#elif defined(CONFIG_VIDEO_AM335X)

enum panel_type
{
    QVGA = 0,
    WVGA,
};

enum panel_shade
{
    MONOCHROME = 0,
    COLOR_ACTIVE,
    COLOR_PASSIVE,
};

typedef struct vidinfo
{

    ushort  vl_col;     /* Number of columns (i.e. 160) */
    ushort  vl_row;     /* Number of rows (i.e. 100) */
    u_char  vl_bpix;    /* Bits per pixel, 0 = 1 */

//---- Frame buffer parameter.
    enum panel_type panel_type ;
    int max_bpp;
    int min_bpp;
    enum panel_shade panel_shade;

    int ac_bias;        /* AC Bias Pin Frequency */
    int ac_bias_intrpt;   /* AC Bias Pin Transitions per Interrupt */
    int dma_burst_sz; /* DMA burst size */
    int bpp;    /* Bits per pixel */
    int fdd;     /* FIFO DMA Request Delay */

    /* TFT Alternative Signal Mapping (Only for active) */
    unsigned char tft_alt_mode;
    /* 12 Bit Per Pixel (5-6-5) Mode (Only for passive) */
    unsigned char stn_565_mode;

    /* Mono 8-bit Mode: 1=D0-D7 or 0=D0-D3 */
    unsigned char mono_8bit_mode;
    unsigned char sync_edge;          /* Horizontal and Vertical Sync Edge: 0=rising 1=falling */
    unsigned char sync_ctrl;         /* Horizontal and Vertical Sync: Control: 0=ignore */
    unsigned char raster_order;   /* Raster Data Order Select: 1=Most-to-least 0=Least-to-most */
    int fifo_th;        /* DMA FIFO threshold */

//---- LCD Panel data
    unsigned short  width;
    unsigned short  height;
    int     hfp;        /* Horizontal front porch */
    int     hbp;        /* Horizontal back porch */
    int     hsw;        /* Horizontal Sync Pulse Width */
    int     vfp;        /* Vertical front porch */
    int     vbp;        /* Vertical back porch */
    int     vsw;        /* Vertical Sync Pulse Width */
    unsigned int    pxl_clk;    /* Pixel clock */
    unsigned char   invert_pxl_clk; /* Invert Pixel clock */
    unsigned char invert_line_clock;         /* Invert line clock */
    unsigned char invert_frm_clock;      /* Invert frame clock  */

//---- par parameter.
    unsigned long   pseudo_palette[32];
    unsigned char   *v_palette_base;
    unsigned int    palette_sz;
    void            *video_mem;

}vidinfo_t;

注意事項.
Driver 其實只要 implentment 下列這三個 function 就可以了.
其中要注意 setcolreg 的function , AM335x TFT 24/32 BPP 沒有 調色盤 , 不需要
設定..


void lcd_setcolreg(ushort regno, ushort red, ushort green, ushort blue);
void lcd_ctrl_init(void *lcdbase);
void lcd_enable(void);

打完收工.......